Photo-induced spin and valley-dependent Seebeck effect in the low-buckled Dirac materials

TL;DR

This paper investigates how light and electric fields influence the spin and valley-dependent Seebeck effects in low-buckled Dirac materials, revealing controllable spin and valley polarization of thermovoltage.

Contribution

It introduces a theoretical analysis of the spin and valley Seebeck effects in irradiated LBDMs, highlighting the control of thermovoltage polarization via light polarization and electric fields.

Findings

Seebeck coefficients exhibit odd symmetry with respect to chemical potential.

Thermovoltage can be spin or valley polarized depending on external controls.

Reversing light polarization or electric field direction inverts the polarization of thermovoltage.

Abstract

Employing the Landauer-Buttiker formula we investigate the spin and valley dependence of Seebeck effect in low-buckled Dirac materials (LBDMs), whose band structure are modulated by local application of a gate voltage and off-resonant circularly polarized light. We calculate the charge, spin and valley Seebeck coefficients of an irradiated LBDM as functions of electronic doping, light intensity and the amount of the electric field in the linear regime. Our calculation reveal that all Seebeck coefficients always shows an odd features with respect to the chemical potential. Moreover, we show that, due to the strong spin-orbit coupling in the LBDMs, the induced thermovoltage in the irradiated LBDMs is spin polarized, and can also become valley polarized if the gate voltage is applied too. It is also found that the valley (spin) polarization of the induced thermovoltage could be inverted by reversing the circular polarization of light or reversing the direction the electric field (only by reversing the circular polarization of light).